Process of preparing alkaryl sulfonates by dimerizing olefins with a metal oxide promoted silica-alumina catalyst



United States Patent 3,332,989 PROCESS OF PREPARING ALKARYL SULFO- NATESBY DIMERIZING OLEFINS WITH A METAL OXIDE PROMOTED SILICA-ALUMI- NACATALYST Joseph Q. Snyder, St. Charles, and'Robert D. Swisher,.Kirkwood, Mo., William E. Weesner, Dayton, Ohio, and Lionel T. Wolford,Endwell, N.Y., assignors to Monsanto Company, St. Louis, Mo., acorporation of Delaware No Drawing. Filed Feb. 23, 1965, Ser. No.434,624

8 Claims. (Cl. 260-505) The present invention relates to a process forthe preparation of alkyl aromatic sulfonates. More particularly, thepresent invention relates to a process for the preparation of olefinhydrocarbons'and their incorporation into alkyl aromatic sulfonatecompositions. Still more particularly, the present invention relates toa process for the ultimate production of alkyl aromatic sulfonatecompositions havingthe property of being susceptible to biologicaldecomposition.

At present, the majority of the commercially available detergentscontain alkylbenzene sulfonates or other alkyl aromatic sulfonates asthe active ingredient. These alkylbenzene sulfonates, though havingexcellent detergent properties, are highly resistant to biologicaloxidation or, as otherwise known, biodegradation. Because of thisresistance to decomposition by biological means, considerable amounts ofthese detergent compounds pass through sewage or waste disposal plantsunchanged. The presence of the undecomposed detergent causes difiicultyin operating the disposal plants and further, after leaving the disposalplants, is responsible for unsightly nuisances and represents potentialtoxicity hazards to aquatic life and to communities downstream. Thisproblem is receiving rapidly increasing attention from public healthoflicials, sanitary engineers and the detergent industry. In severalcountries of Europe, the problem has become so acute as to inspiregovernmental action relative to the control of the manufacture ofalkylbenzene sulfonate detergents.

The alkylbenzene sulfonates presently used in the detergent industry, toa large extent derive their alkyl substituents from olefin polymers,with the most commonly used polymers being propylene tetramers,pentamers, and fractions intermediate between these two. Thesepropylene-derived polymers are produced largely by the polymerization ofpropylene over phosphoric acid catalysts. The alkylbenzene sulfonatesprepared from these phosphoric acid polymerization products are, as arethose prepared from many other such olefin polymers, highly resistant tobiological oxidation.

It is an object of the present invention to provide a process for thepolymerization of olefin hydrocarbons. It is also an object of thepresent invention to provide a process for the preparation of alkylaromatic sulfonate compositions. Another object of the present inventionis to provide a process for the dimerization and/or codimerization ofstraight-chain mono-olefin hydrocarbons. Yet another object of thepresent invention is to provide a process for the production of olefinpolymers which are significantly more susceptible to biologicaldecomposition than those provided by presently known processes. A moreparticular object of the present invention is to provide a process forthe preparation of alkyl aromatic sulfonate detergent compositions whichare substantially less resistant to biological decomposition than thosepresently known, wherein the alkyl substituents to the alkyl aromaticsulfonate are obtained by the dimerization and/or co-dimerization ofstraight-chain monoolefin hydrocarbons. Additional objects will becomeapstraight-chain mono-olefin hydrocarbons 3,332,989 Patented July 25,1967 parent from the following description of the invention hereindisclosed.

In fulfillment of these and other objects, it has been found thatcertain specifically prepared alkyl aromatic sulfonates possess theproperty of being susceptible to biological decomposition. The processwhereby these specifically prepared alkyl aromatic sulfonates are formedcomprises contacting a hydrocarbon feed containing at least onestraight-chain mono-olefin hydrocarbon of 5 to 12 carbon atoms selectedfrom the group consisting of alpha-olefins and internally unsaturatedolefins with a catalyst selected from the group consisting of syntheticsilica-alumina, naturally occurring silica-alumina and metal oxidepromoted silica-alumina catalyst when said mono-olefin is an internallyunsaturated olefin and with a metal oxide promoted silica-alumina whensaid monoolefin is an alpha-olefin, at a temperature ranging from 50 to250 C. and a pressure of atmospheric to 2000 p.s.i., thereby forming aproduct containing substantial amounts of polymers formed by thecondensation of two molecules or monomer units and having a number ofcarbon atoms equal to the sum of the carbon atoms contained in any twostraight-chain mono-olefin hydrocarbon molecules, like or unlike, withinthe hydrocarbon feed, and thereafter subjecting said product todistillation and recovering therefrom a fraction consisting essentiallyof the polymers formed by the condensation of two straight-chainmono-olefin molecules and then subjecting said fraction to alkylationconditions in the presence of an aromatic hydrocarbon and a suitablealkylation catalyst, thereby producing alkyl aromatic hydrocarbonscontaining as the alkyl substituents the polymers formed by the union oftwo straight-chain mono-olefin molecules, and thereafter subjecting thealkyl aromatic hydrocarbons to sulfonation and subsequent neutralizationthereby producing alkyl aromatic sulfonates. The alkyl aromaticsulfonates thus produced are significantly more susceptible tobiological decomposition than those of comparable molecular weightsproduced by presently known methods.

The process of the present invention as disclosed above comprises threecritical steps. These three steps are: first, the polymerization ofolefin hydrocarbons to produce alkyl substituents to the alkyl aromaticsulfonates; second, the alkylation of an aromatic hydrocarbon with thepolymers of the first step; and third, the sulfonation of the alkylaromatic hydrocarbons produced in the second step. The first stepproduces two types of polymers, depending upon the hydrocarbon feed tothe polymerization reaction. The two types of polymers are dimers andco-dimers. If the hydrocarbon feed contains only straightchainmono-olefin hydrocarbons of a single molecular Weight such as C then theproduct would be a C hydrocarbon which is the dimer of the C On theother hand, if the hydrocarbon feed contains, for example, three ofdiiferent molecular weights and each having 5 to 12 carbon atoms such asa hydrocarbon feed containing C C and C hydrocarbons, then the productwould contain not only true dimers of each of the feed hydrocarbons butalso their co-dimers. The products of such a hydrocarbon feed y berepresented as 5) 02, 02, 5- 6) (C -C and (C5C'7), with the first threebeing the true dimers of the C C and C feed hydrocarbons and the latterthree being the co-dimers of these feed hydrocarbons. Dimerization isthen the condensation, one with another, of two like olefin molecules ormonomer units while co-dimerization is the condensation, one withanother, of two unlike olefin molecules or monomer units. The secondstep of the present invention, the alkylation step, produces alkylaromatic hydrocarbons having these dimers and/or co-dimers as alkylsubstituents thereto. Alkylation of aromatic hydrocarbons with thesedimers and/or co-dimers may be carried out by conventional, well knownmethods. The third step in the process of the present invention is thesulfonation of the alkyl aromatic hydrocarbons produced by the secondstep. Sulfonation, also, may be carried out by any of the conventionaland Well known techniques. Intermediate between these three steps aresuch incidental but necessary actions as distillation, neutralization,etc. These intermediate actions are readily within the ability of anyoneskilled in the art and the methods are not critical and are well known.

To further describe and to illustrate the present invention, thefollowing examples are presented. These examples are not, however, to beconstrued in any manner as limiting the application, conditions, orobjects of the present invention.

EXAMPLE I Approximately 2.4 moles of 2-hexene were placed in anevacuated autoclave with approximately 24 grams of a catalyst containing82.6 percent by weight SiO 11.8 percent by weight A1 and 5 percent N10.The catalyst was activated by heating in air at 500 C. to 600 C. for 12hours. The olefin-catalyst mixture was stirred for approximately 6hours. During this period the reaction mass was maintained at atemperature of 155 to 175 3. The reaction pressure was initiallyatmospheric but was allowed to rise autogenously. At the completion of:he reaction period, agitation was stopped and the liquid separated fromthe catalyst by decantation. The recovered iquid was then subjected todistillation and separated into :hree fractions. The first fractionrepresented 38.2 weight qercent of the recovered liquid and wasunreacted hexenes. The second fraction was a C or hexene dimer fraction1nd represented 40.6 weight percent of the recovered iquids, and thethird fraction was principally hexene :rimer and tetramer andrepresented 21.2 weight percent )f the recovered liquids. The hexenedimer fraction con- ;tituted 65.7 weight percent of the polymerizedproduct.

EXAMPLE II The C or hexene dimer fraction obtained in Example I was usedto alkylate benzene by adding the C fracion dropwise to dry benzenewhich had been previously laturated with gaseous HCl and to which hadbeen added tluminum chloride. The mixture was agitated throughout headdition. The ratio of aluminum chloride to benzene vas 0.013:1 and theratio of the C fraction to benzene vas 0.39:1. The reaction mixture wasmaintained at a emperature of approximately 35 to 37 C. throughout headdition of the C material. After completion of the vddition of the Chydrocarbons, agitation of the mixure was continued until reaction wascomplete. The reacion mass was then allowed to settle into two layers,an lkylated layer and a catalyst complex layer. The alkylted layer wasrecovered and washed twice with equal olumes of water and thenfractionally distilled to reover the C alkylbenzene fraction. Thisfraction repreented approximately 75 weight percent of the alkylateiyer.

Sulfonation was then begun by charging alkylbenzene tom the fractionaldistillation to a sulfonation vat. A lass container was used. Thetemperature was lowered approximately 10 to C. by means of an ice bathrid then percent oleum was added dropwise with con- :ant agitation. Theamount of oleum added was aproximately 1% times the weight of the Calkylbenzene. he temperature was maintained at 20 C.i5 C. iroughout theaddition of the oleum. After completion E the oleum addition, theagitation was increased in [tensity and the temperature raised andmaintained for me hour at 40 C.:2 C. At the end of the hour, water 'asadded to quench the reaction with the temperature sing kept below 60 C.The agitation was stopped and le mixture was allowed to separate intotwo layers. The

upper layer was recovered and neutralized with 50 percent sodiumhydroxide. The product thus obtained was the alkylbenzene sulfonateprepared from the dimer of 2-hexene.

EXAMPLE III 2-hexene was dimerized at a temperature of 150 C. in thesame manner as set out in Example I with the exception that the catalystwas an acid clay designated as K10SF23 from Sud-Chernie A.G., Munich,Germany. This catalyst is an acid-treated montmorillonite having acomposition of 5 0 to 70 percent silica, 15 to 20 percent alumina, 3 to5 percent Fe O 1 to 3 percent CaO, and 1 to 3 percent MgO. The recoveredZ-hexene dimer product represented a conversion of 34.6 percent.

EXAMPLE IV Approximately 3.0 moles of Z-heptene were placed in anevacuated autoclave with approximately 26 grams of a silica-aluminacatalyst. The catalyst contained 87 percent by weight SiO and 13 percentby weight A1 0 and was activated by heating in air at 500 to 600 C. for12 hours. The olefin-catalyst mixture was stirred for approximately 6hours. During this period the reaction mass was maintained at to C. Thereaction pressure was initially atmospheric but was allowed to riseautogenously. At the completion of the reaction period, the liquid wasseparated from the catalyst by decantation. The recovered liquid wasthen subjected to distillation and separated into three fractions. Thefirst fraction represented 47.2 weight percent of the recovered liquidand was unreacted heptenes. The second fraction was the heptene dimerproduct and represented 34.5 weight percent of the recovered liquids,and the third fraction was principally heptene trimer and tetramer andrepresented 18.3 weight percent of the recovered liquids. The heptenedimer fraction, which constituted 65.3 weight percent of the polymerizedproduct, had a boiling range of 94 to 105 C. at mm. Hg.

EXAMPLE V The C 2-hexene dimer fraction from Example III and the2-heptene dimer from Example IV were subjected to reaction with benzeneto form an alkylbenzene which was then in turn sulfonated to form analkylbenzene sultonate. The methods of alkylation and sulfon-ation werethe same as those of Example II.

EXAMPLE VI Approximately 1.5 moles of 2-hexene and 1.5 moles of 2-octenewere placed in an evacuated autoclave with approximately 45 grams of acommercial, synthetic silicaalumina catalyst. The silica-aluminacatalyst was one containing 87 percent by weight SiO and 13 percent byweight A1 0 The catalyst was activated by heating in air at 500 to 600C. for 12 hours. Next,the olefincatalyst mass was agitated forapproximately 4 hours during which time the reaction mass was maintainedat a temperature of 146 to 150 C. The reaction pressure was initiallyatmospheric but was allowed to rise autogenously. At the completion ofthe reaction period, agitation was stopped and the liquid separated fromthe catalyst by decantation and then subjected to distillation to removethe unreacted C and C mono-olefin hydrocarbons. The remaining liquidproduct, representing a yield of 59.7 percent was then analyzed bylow-voltage mass spectrometry with the following results:

Mono-olefin: Weight percent of produc c 3.4 C 13.1 C 1.1 C 32.6 C 1.3 C13.9

2-hexene molecule with a 2-octene molecule and is thus 5 a co-dirner.Trimerization or co-trimerization products are found in the 0 portion ofthe polymer product. The C C .and C fractions very probably representthe products cracking back and disproportionation of C C C and C plusfractions.

EXAMPLE VII The product obtained in Example VI was fractionated and a Cto C fraction recovered. This C to C fraction was subjected to reactionwith benzene to form an alkylbenzene which was subsequently sulfonatedto produce alkylbenzene sulfonates. The methods used for alkylation andsulfonation were the same as used in Example II.

EXAMPLE VIII To illustrate the biodegradability of these alkylbenzenesulfonates prepared according to the process of the present invention,alkylbenzene sulfonates prepared in Examples II and V were compared withan alkylbenzene sulfonate prepared from propylene tetramer by the 2method of Example II. The propylene tetramer was obtained by thepolymerization of propylene over a phosphoric acid catalyst as set outin US. Patent No. 2,057,- 433. In comparing the conventionally-preparedpropylene tetramer containing alkylbenzene sulfonate with 'thealkylbenzene sulfonates prepared according to the present invention, theRiver Water Test was applied. This test is a comparison type test and assuch is indicative of the relative rates of biological decomposition ofany number of different compounds being tested. The specificconcentration of alkylbenzene sulfonate in the river water is determinedby the methylene blue test, which comprises introducing methylene blueinto a sample of the alkylbenzene sulfonate containing river water,thereby producing a salt of the alkylbenzene sulfonate with themethylene blue. This salt is then extracted with an organic solvent suchas chloroform and the solution color measured. The methylene blueanalysis used herein is described in The Analyst, vol. 62, 826-27(1957). The rate and amount of the reduction of concentration ofalkylbenzene sulfonate in the mixture is a comparative measure of itssusceptibility or, conversely, resistance to bacterial attack.

A sample of river water was obtained and separated into two equalportions, each in a separate vessel. To

one of these portions was added an amount of the alkylbenzene sulfonateprepared in Example II sufiicient to bring about a concentration of 7.0parts per million of the alkylbenzene sulfonate in the river water. Tothe other portion of the river water was added the dodecylbenzenesulfonate prepared from propylene tetramer ob- 5 tained from theconventional phosphoric acid polymerization of propylene. The amount ofthis conventional dodecylbenzene sulfonate added was sufiicient to bringabout a concentration of 8.4 parts per million of the conventionaldodecylbenzene sulfonate in the river water.

The concentration of the alkylbenzene sulfonates in the river water wasthen determined at 0, l0, and 20 days. This comparison was then repeatedwith one of the alkylbenzene sulfonates prepared in Example V. Thefollowing table summarizes the data thus obtained. The al kylbenzenes inthe table are described according to the example in which they wereprepared and the olefin fraction used in the preparation.

Concentration in p.p.m.

Alkylbenzene Sulionate 0 10 20 30 50 days days days days daysOla-tetramer derived 6. 8 5. 3 1. 8 1. 6 1. 6 Example II (derived fromEx. I) 6. 8 4. 5 0.7 0. 6 0. 5 (la-tetramer derived 6. 8 5.8 2. 6 2.0 1. 8 Example V (derived from Ex. III) 7.0 4.1 0.5 0.4 3

EXAMPLE IX To illustrate the biodegradability of the alkylbenzenesulfonate prepared in Example VII, the Sludge Efiluent Test was used.This test is identical to the River Water Test with the exception thatan efiluent from an activated sludge sample is used to provide thebacteria rather than the river water. More specifically, a sample ofsludge is obtained from an activated-sludge sewage disposal plant. Thissludge sample is fed nutrients at approximately 24 hour intervals. Thesample is maintained at room temperature and under normal lightingconditions and is continuously agitated by a stream of air introducednear the bottom of the sludge receptacle. The liquid effluent decantedfrom such a culture after settling is then used in exactly the samemanner as the river water in the River Water Test described in ExampleVIII.

The following table gives the results of this test in comparingdodecylbenzene prepared from propylene tetramer as described in ExampleVIII with the alkylbenzene sulfonate prepared in Example VII.

0 days 10 days (la-tetramer derived 5. 9 5. 5 Example VII (derived fromEx. VI) 4. 9 3.0

From the above Examples VHI and IX, it becomes readily apparent that thealkylbenzene sulfonates prepared in accordance with the herein-disclosedinvention are substantially more susceptible to biological decompositionthan those prepared in the conventional manner as derivatives ofpropylene tetramer.

The present invention is further illustrated by the preparation of analkyl aromatic sulfonate using as the aromatic hydrocarbon toluene andas the alkyl substituent thereto, a C fraction obtained'by thedimerization of 1- hexene over a catalyst comprised of 87 percent byweight silica, 12 percent by weight alumina, and 1 percent by weightnickel oxide. The alkyl aromatic sulfonate thus prepared issignificantly more susceptible to biological decomposition than those ofcomparable molecular weights prepared according to convention-a1 knownmethods.

The invention is still further illustrated by other examples whereinnaphthalene, mixed xylenes, ortho-xylene, meta-xylene, para-xylene,ethylbenzene, methylnaphthalene, ethylnaphthalene, or dimethylnaphthalene is used in place of the benzene recited in ExamplesII, V and VII.

In preparing the alkylbenzene sulfonates according to the presentinvention, it is necessary as a first step to dimerize and/orco-dimerize straight-chain mono-olefin hydrocarbons. The feedstockswhich may be used in this first step to the present invention are thoseconsisting essentially of straight-chain mono-olefin hydrocarbons,either alpha-olefins or internally unsaturated olefins. Such feedstocksmay contain only one of such hydrocarbons or may contain two or more ofsuch hydrocarbons of the same or different molecular weights. Itis'preferred hat the straight-chain mono-olefin hydrocarbons contain ito 12 carbon atoms and more preferred that they have i to 10 carbonatoms. These feedstocks should contain greater than 10 weight percent ofbranched-chain mono-olefin hydrocarbons. It is preferred, however, that[0 branched-chain mono-olefin hydrocarbons be present 11 the feed. Also,it is preferred that there be no acetylines or diolefin hydrocarbons asimpurities in the feed. iaturated hydrocarbons, e.g., paraflins, havelittle or no leleterious effect on the present invention, and, thereore,their concentration in the feed is not critical to he operation of thepresent process. However, excessive .mounts of saturated hydrocarbonsshould be avoided rom a practical standpoint since they are merely deadveight to the process. Examples of the straight-chain mono-olefinhydrocarbons to which the present invention specifically directed arel-pentene, 2-pentene, l-hexene, .-hexene, 3-hexene, l-heptene,2-heptene, 3-heptene, 1- ctene, 2-octene, 3-octene, 4-octene, l-nonene,2-nonene, -nonene, 4-nonene, l-decene, 2-decene, 3-decene, 4- lecene,S-decene, etc., up to and including 6-dodecene. The number ofstraight-chain mono-olefin hydrocarbons If different molecular weightswhich may be present in he hydrocarbon feed is immaterial, butgenerally, for implicity of operation, it is preferred, if more than onere present, to have not more than 5 straight-chain monollefinhydrocarbons of different molecular weights in the mixture. Thehydrocarbons of a particular molecular veight included within thehydrocarbon feed mixture may be any or any mixture thereof of the doublebond somers of that molecular weight which is within the ;enericdescription of the preferred feeds subject to the imitations hereinbelowset forth in regard to catalysts. or example, a feed containing C and Cstraight-chain mono-olefin hydrocarbons may include l-hexene, 2-hexne,3-hexene, or any mixture thereof as the C hydroarbons and l-octene,2-octene, 3-octene, 4-octene, or any mixture thereof as the Chydrocarbons.

The catalysts which may be used in bringing about his dimerization andco-dimerization of the straight- :hain mono-olefin hydrocarbonsaccording to the pracice of the first step of the present invention maybe lroadly classed as those containing silica and alumina, magnesia,titania, or zirconia. These catalysts may be hose containing only silicaand alumina, magnesia, tiania, or zirconia or they may contain, inaddition, 'arious metal oxides as polymerization promoters. Nonimitingexamples of catalysts within the scope of the iresent invention are suchcatalysts as silica-alumina, ilica-magnesia, silica-titania, andsilica-zirconia catalysts :ontaining 1 to 99 percent by weight silicaand the remainder alumina, magnesia, titania, or zirconia and inertmaterials, silica-alumina, silica-magnesia, silica-titania,ilica-zirconia catalysts containing 0.001 to 15 percent by veight of oneor more metal oxide promoters, naturallylccurring silica and aluminacontaining acid clays such .s kaolin, montmorillonite, fioridin, etc.Metal oxide promotors which may be used with these catalysts are theoxdes of metals from Groups IA, IIA, IVB, VB, VIB, VIII, B, HE, and IIIAof the Periodic Table. Somewhat more )referred catalysts for causing thedimerization and colimerization of the straight-chain mono-olefinhydrocarlons in accordance with the present invent-ion are cattlYStSconsisting essentially of silica and alumina in a veight ratio of 1: 10to 10:1 of silica to alumina and also raving included as a portionthereof one or more metal )xides selected from the group consisting oflithium, odium, potassium, rubidium, cesium, calcium, titanium,'anadiurn, chromium, molybdenum, manganese, iron, uthenium, cobalt,nickel, palladium, platinum, copper, ilver, zinc, cadmium, mercury, andgallium. Still more ireferred are those catalysts which consistessentially of .ilica and alumina in a weight ratio of 1:3 to 8:1 of;ilica to alumina and silica-alumina catalysts having this veight ratioof silica to alumina but also containing 0.001

to 10 percent by weight of a metal oxide promoter selected from thegroup consisting of the oxides of lithium, potassium, nickel, copper,and gallium. Also among the preferred catalysts are thenatural-occurring acid clays previously mentioned, kaolin,montmorillonite, and floridin.

One important limitation on the choice of catalysts for use in theprocess of the present invention is in regard to the feed used. If thefeed is one comprising internally unsaturated mono-olefins, then any ofthe above defined catalysts may be used. However, if the feed is oneconsisting essentially of straight-chain alpha-olefins, then thecatalyst used is one of the above-described metal oxide promotedsilica-alumina catalysts.

The temperatures at which dimerization and co-dimerization of thestraight-chain mono-olefin hydrocarbons may be effectively carried outmay range from 50 to 250 C. A somewhat more preferred temperature range,however, is to be found from approximately to 200 C. Temperatures foroptimum results will vary considerable with the different dimerizationand co-dimerization catalysts which are within the scope of the presentinvention and also the optimum temperatures will vary with feed-stocks,method of contact, pressures, etc. Determination of optimum temperatureswithin the above ranges are readily within the ability of those skilledin the art, however.

Pressures wherein the process of the first step of the present inventionis operable may range from atmospheric to 2000 p.s.i. However, it ispreferable to utilize pressures of approximately atmospheric to 500 psi.It is still more preferred to operate at pressures of atmospheric to 300psi. and still more preferable to operate at or near atmosphericpressure, with the highest pressure attained being in the sum of thepartial pressures of the components of the system at the conditions oftemperature at which the reaction is being carried out.

The method whereby the straight-chain mono-olefi hydrocarbon feed iscontacted with the catalyst is not particularly critical in the presentinvention. Any method insuring thorough contact between the catalyst andthe feed hydrocarbons may be used. If batch type contacting is used, thelength of time of contact may vary as widely as 0.1 to 24 hours with theoptimum contact time being dependent on such things as the specificcatalyst used, the feedstocks, temperatures, eificiency of contact, etc.Optimum contact times may be readily determined by anyone skilled in theart by application of the teachings herein presented concerning theother process variables of the present invention. When and if it ispreferred to have a continuous process using the present invention,space velocities of the reactants will become of some importance but maybe readily determined by those skilled in the art and having knowledgeof the temperatures and pressures, feedstocks, etc., given herein.Generally, however, space velocities will range within 0.01 to 10.0pounds of liquid feed per hour per pound of catalyst. In many instances,prior polymerization art may provide a guide for the determination ofspace velocity ranges for certain of the catalysts operable in thepresent invention. Length of contact time, whether in a continuous orbatch type process will generally have little effect on the structure ofthe product.

The present invention may be utilized for the preparation of alkylaromatic sulfonates in which the aromatic portion is any aromatic oralkyl aromatic hydrocarbon having alkyl side chains of a length suchthat they will not destroy the detergent properties of the alkylaromatic sulfonate. The aromatic nucleus may be benzenoid ornaphthalenoid. The substituents to the aromatic nucleus should notcontain more than 4 carbon atoms each and there should be no more than 4of such alkyl substituents to the aromatic nucleus. Several non-limitingexamples of aromatic hydrocarbons other than benzene which may bealkylated and sulfonated according to the present invention to producealkyl aromatic sulfonates which are susceptible to biologicaldecomposition are the following: naphthalene, toluene, omand p-xylenes,ethylbenzene, methylnaphthalenes, ethylnaphthalenes,dimethylnaphthalenes, etc.

The products formed by the dimerization and co-dimerization ofstraight-chain mono-olefin hydrocarbons and discussed above may be usedin the alkylation of benzene, either individually or in fractionscontaining two or more products. In instances where the product carbonnumber distribution is such that two or more carbon atoms separate eachdimer and/ or co-dimer product, it may be desired to use only anindividual compound of a desired molecular weight due to the relativeease with which such widely spaced products may be separated bydistillation, or it may he desired to use mixtures of differentmolecular weight products. In instances where the difierent products areseparated by only one carbon atom, fractions containing two, three, orfour dilferent products will probably be more generally used though, ifdesired, the fractions may be separated into component parts and theseused for alkylation. Since all of the products of the union of twomolecules or monomer units formed by the dimerization andco-dimerization of straight-chain mono-olefin hydrocarbons of to 12carbon atoms in accordance with the present invention will formalkylbenzene sulfonates susceptible to biological decomposition, thenthey may be utilized equally well whether as individual compounds or asfractions containing two or more of such compounds.

The dimers and co-dimers of the straight-chain monoolefin hydrocarbons,once obtained, must then be reacted with benzene to form analkylbenzene. This may be accomplished, with not necessarily equivalentbut with adequate results, by using any of the catalysts and methodspresently known to the art and is not critical in the present invention.The method used in Example 11 is somewhat preferred, however, it beingvery practical and one which gives very satisfactory results.

The sulfonation of the alkylbenzene to produce an alkylbenzene sulfonatealso follows conventional and well known methods. As in the case of thealkylation step of the present invention, abundant prior art exists asto the sulfonation of alkylbenzenes to produce alkylbenzene sulfonatedetergents. Any of the methods of the prior art may be utilized, notnecessarily with equivalency, but with adequate results. Generally,however, the method set forth in Example 11 is somewhat preferred, itbeing a conventional and well known method and one which gives verysatisfactory results.

We claim:

1. A process for the preparation of biodegradable alkyl aromaticsulfonates which comprises contacting a hydrocarbon feed consistingessentially of straight-chain monoolefin hydrocarbons having 5 to 12carbon atoms with a silica-alumina catalyst having a weight ratio ofsilica to alumina of 1:10 to 10:1 and containing 0.001 to 15 percent byweight of a metal oxide promoter, said metal oxide promoter beingselected from the group consisting of the oxides of lithium, potassium,nickel, copper, and gallium, at a temperature of 50 to 250 C. and at apressure of atmospheric to 2000 p.s.i., thereby forming a productcontaining substantial amounts of polymers formed by the condensation oftwo molecules of the feed hydrocarbons and having numbers of carbonatoms equal to the sum of the carbon atoms contained in any twostraight-chain mono-olefin hydrocarbon molecules within the hydrocarbonfeed, and thereafter subjecting said product to distillation andrecovering therefrom a fraction containing the polymers formed by thecondensation of two straightchain mono-olefin molecules, and thensubjecting said fraction to alkylation conditions in the presence of anaromatic hydrocarbon and a suitable alkylation catalyst, therebyproducing alkyl aromatic hydrocarbons containing as the alkylsubstituents the polymers formed by the union of two straight-chainmonoolefin hydrocarbon molecules, and thereafter subjecting thealkylaromatic hydrocarbons to sulfonation, thereby producing alkylaromatic sulfonates.

2. The process of claim 1 wherein the hydrocarbon feed is contacted withthe catalyst at a temperature of to 200 C. and a pressure of atmosphericto 500 p.s.i.

3. The process of claim 1 wherein the weight ratio of silica to aluminais 1:3 to 8:1.

4. The process of claim 1 wherein the amount of said metal oxidepromoter present in said silica-alumina catalysts is 0.001 to 10 percentby weight of the catalyst.

5. The process of claim 1 wherein the straight-chain mono-olefinhydrocarbons in said hydrocarbon feed have References Cited UNITEDSTATES PATENTS 3/1958 Hogan et al. 260-88.1 6/1965 Gudelis 260-505LORRAINE A. WEINBERGER, Primary Examiner.

WEBSTER, Assistant Examiner.

1. A PROCESS FOR THE PREPARATION OF BIODEGRADABLE ALKYL AROMATICSULFONATES WHICH COMPRISES CONTACTING A HYDROCARBON FEED CONSISTINGESSENTIALLY OF STRAIGHT-CHAIN MONOOLEFIN HYDROCARBONS HAVING 5 TO 12CARBON ATOMS WITH A SILICA-ALUMINA CATALYST HAVING A WEIGHT RATIO OFSILICA TO ALUMINA OF 1:10 TO 10:1 AND CONTAINING 0.001 TO 15 PERCENT BYWEIGHT OF A METAL OXIDE PROMOTER, SAID METAL OXIDE PROMOTER BEINGSELECTED FROM THE GROUP CONSISTING OF THE OXIDES OF LITHIUM, POTASSIUM,NICKEL, COPPER, AND GALLIUM, AT A TEMPERATURE OF 50 TO 250*C. AND AT APRESSURE OF ATMOSPHERIC TO 2000 P.S.I., THEREBY FORMING A PRODUCTCONTAINING SUBSTANTIAL AMOUNTS OF POLYMERS FORMED BY THE CONDENSATION OFTWO MOLECULES OF THE FEED HYDROCARBONS AND HAVING NUMBERS OF CARBONATOMS EQUAL TO THE SUM OF THE CARBON ATOMS CONTAINED IN ANY TWOSTRAIGHT-CHAIN MONO-OLEFIN HYDROCARBON MOLECULES WITHIN THE HYDROCARBONFEED, AND THEREAFTER SUBJECTING SAID PRODUCT TO DISTILLATION ANDRECOVERING THEREFROM A FRACTION CONTAINING THE POLYMERS FORMED BY THECONDENSATION OF TWO STRAIGHTCHAIN MONO-OLEFIN MOLECULES, AND THENSUBJECTING SAID FRACTION TO ALKYLATION CONDITIONS IN THE PRESENCE OF ANAROMATIC HYDROCARBON AND A SUITABLE ALKYLATION CATALYST, THEREBYPRODUCING ALKYL AROMATIC HYDROCARBONS CONTAINING AS THE ALKYLSUBSTITUENTS THE POLYMERS FORMED BY THE UNION OF TWO STRAIGHT-CHAINMONOOLEFIN HYDROCARBON MOLECULES, AND THEREAFTER SUBJECTING THEALKYLAROMATIC HYDROCARBONS TO SULFONATION, THEREBY PRODUCING ALKYLAROMATIC SULFONATES.